Inflatable foldable structure and method of manufacturing foldable structures

ABSTRACT

The application of technically sensitive devices in outer space requires adequate protective shields or protective chambers which protect the payload against atmospheric radiation, thermal effects etc. 
     The foldable structure according to the invention consists of a topological arrangement of flexible tubes which are joined to each other and form the skeleton of the shield or of the chamber. To these tubes there are attached membranes which serve as protective walls. 
     The method of manufacturing a finished protective device uses such a foldable structure, whereby the structure is unfolded by inflation of the tubes and assumes the desired two-dimensional or three-dimensional form. The membranes are also stretched by the extension of the tubes and the interaction of the membranes and the tubes, such tubes acting as struts in the inflated condition, produces a stable structure. 
     The foldable structure according to the invention and the method of manufacturing render possible that devices having dimensions of and more meters can be easily erected with high reliability. Since the structure in the unfolded condition is stabilized by the tubes, non-closed surfaces or protective chambers comprising hatches can also be manufactured in contrast to balloon-type bodies known so far.

CROSS-REFERENCE TO RELATED PATENT

This application is related to the commonly assigned U.S. Pat. No.4,755,819 granted Jul. 5, 1988, entitled "REFLECTOR ANTENNA AND METHODOF FABRICATION".

BACKGROUND OF THE INVENTION

The present invention relates to new and improved inflatable foldablestructures for protective devices or other auxiliary devices, their useas protective shields and protective chambers for shielding pay loads inouter space, and a method of manufacturing foldable structures.

The use of sensitive technical devices in outer space requiresprotective shields or protective shrouds which protect the correspondingdevices against cosmic and electromagnetic radiation, solar action,meteorites etc. Furthermore, auxiliary devices are required in order tomaintain defined atmospheric conditions or ambient temperatures forcertain pay loads or in order to protect experiments or a specificworking area from outer space. Stringent requirements are demanded ofsuch auxiliary devices or protective devices, such requirementsdepending on the specific operational system of the devices. In additionto a high reliability during unfolding and in operation, there existrequirements such as a low weight and a small storage volume whilepossessing a sturdy construction, as well as a lowest possible price.Furthermore, it is above all of importance that the device in theoperating condition can attain large overall dimensions, typically 10meters and more.

Known devices of this type cannot be applied for larger constructionsbecause of their complexity, their dimensions or the too high cost andhave therefore structure dependent limits. Particularly, mechanicalself-opening devices of larger dimensions are thereby not anymoreapplicable. Conventional protective shields as used in conjunction withcryostats are not unfoldable and possess small dimensions. Furthermore,known balloon-type inflatable chambers permit only very limitedoperational possibilities on account of their form, since essentiallyonly ball-shaped or lense-like forms are possible. Moreover, suchinflatable devices have the major disadvantage that it is hardlypossible to provide openings in the surface, which openings would allowto subsequently place further objects within the chambers.

SUMMARY OF THE INVENTION

It is one object of the invention to provide a method of manufacturingprotective devices for application in outer space, so that also largepay loads can be partially shielded or entirely enclosed by means ofsuch a device, such devices rendering possible in their geometrysubstantially any two-dimensional or three-dimensional structures andcomplying in optimum manner with the requirements as to low weight,small packaging volume, high reliability, rigidity and low price.

It is a further object of the invention to provide a foldable supportingstructure or a foldable structure which can be used for such protectivedevices, exhibits low weight and can be folded into a small packagingvolume and again unfolded with very high reliability.

Now in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the inflatable foldable structure of the present developmentis manifested, among other things, by the features that, a plurality ofinflatable flexible tubes are joined to form a gas-tight skeleton andthat membranes are attached between the tubes to this skeleton.

The foldable structure according to the invention is composed of atopological arrangement of flexible inflatable tubes which are joined toeach other. At these tubes there are attached membranes which in theunfolded condition form the actual protective walls. Since the tubes aswell as the membranes are formed of plastic material, this foldablestructure is of relatively low weight. Furthermore, there is theadvantage of simple manufacture, any length whatever of the tubes and asmall packaging volume.

The method of manufacturing or producing a finished protective deviceuses such a foldable structure, whereby the structure is unfolded byinflation of the tubes and assumes the desired skeleton-type, forexample, three-dimensional form. By means of selective stretching of thetubes, the membranes are also stretched such that the interaction of themembranes and the tubes, such tubes acting as struts in the inflatedcondition, produce a stable two-dimensional or three-dimensionalstructure. In this manner, a reliable unfolding in outer space isensured. By the use of thermoplastics and a chemically curable coatingof the tubes or of the membranes, the device can be permanently fixed inthe inflated condition without the gas pressure having to be maintainedwithin the tubes.

Brief Description of the Drawings

The method and different exemplary embodiments of the invention will bedescribed in further detail with reference to the following drawings andwherein:

FIG. 1a shows a skeleton for a spherical heat shield according to FIG.1b;

FIG. 1b shows a spherical heat shield having a reflecting plastic foil;

FIG. 2a shows a heat shield having a prismoidal structure;

FIG. 2b shows the base surface of the heat shield according to FIG. 2a;

FIG. 3a shows a prismatic heat shield;

FIG. 3b shows the base surface of the prismatic heat shield as shown inFIG. 3a;

FIG. 4 shows a chamber in the form of a icosahedron;

FIG. 5 shows an annular shading shield having two membranes;

FIG. 6 shows a point of connection between three tube struts; and

FIG. 7 shows a cut-away pattern for a point of connection at which fourtube struts meet.

Detailed Description of the Preferred Embodiments

The method according to the invention renders possible the manufactureof two-dimensional or three-dimensional structures which comprise askeleton-type construction. The form is solely limited by the specifiedtopological requirements of the foldable structures. It is possible tomanufacture with adequate stability structures having overall dimensionsof 10 or more meters.

The skeleton of these structures is composed of individual flexibletubes 11 (FIGS. 1a and 1b) which are joined to each other by means ofcoupling elements 27 as shown in FIG. 2b or are directly joined to eachother at nodal points 16 as shown in FIGS. 1a and 1b. These couplingelements 27 are structured such that an exchange of gas can take placebetween the interior of the individual tubes 22 and 23 (FIG. 2b). If aclosed system is formed in this manner by these tubes 22 and 23, thenthe entire skeleton can be inflated by a pressure source 17 (FIG. 1b)with any suitable gas, for example, nitrogen. It is possibly desirable,particularly in the case of complicated structures, that not all tubesare simultaneously inflated, but that rather a sequential inflationtakes place. For this purpose there can be provided several pressuresources 17 which separately inflate individual areas of the skeleton. Onthe other hand, a sequential inflation of different areas can also beachieved by valves, which only open at a certain gas pressure, or bydiaphragms or other elements influencing the gas flow, for example,constrictions within the tubes. These valves or diaphragms 66 areschematically indicated in FIG. 6 and influence the exchange of gas.Such valves or diaphragms 66, as the case may be, can be provided eitherwithin a tube or in a coupling element. Such a sequential inflationrenders possible the manufacture of complicated structures which can beunfolded with very high reliability.

Since the inflation of the foldable structure takes place in outerspace, minimum pressures in the range of a few millibars are sufficientto effect inflation. Co-transported pressure tanks or gases generatedfrom solid matter by means of chemical reactions are conceivable aspressure sources 17. It is also possible that the foldable structurescan also be unfolded by pouring in liquids which simultaneously can alsoeffect the function of curing the tubes, provided that the total volumeof the tubes is not too large.

Since the tubes 11 have to be flexible and should possess a highrigidity in the unfolded condition, fiber reinforced composite material,for example, is used for the outer walls of the tubes. It is ofadvantage to use for the tubes a material having a smallest possiblebending rigidity, so that the tubes can also be folded along thelengthwise axes thereof and in this manner folded as flat as possible.The outer walls of the tubes can thus be manufactured such that the tubeis curved in the inflated condition.

Membranes can be fastened between the individual tubes 11. In theinflated condition, such membranes form the actual protective walls 14(FIG. 1b) of the protective shield 10.

These membranes are really stretched within the structure predeterminedby the geometry of the inflated skeleton.

It is also possible to achieve a certain slight curvature of a tube inthe inflated condition by the specific form of the membranes. If, forexample, a (straight) tube is attached along a membrane edge whichpossesses a curvature, then the tube subsequent to inflation will extendalong this edge with the same curvature. In this manner, the structurecan be determined in its geometry by the interaction of tubes andmembranes.

The dimensions of such protective devices typically lie within the rangeof 10 to 15 meters. In this dimensional range, tubes having diameters ofapproximately 20 to 50 centimeters are used. Naturally, for specialapplications, elements with larger or smaller dimensions can also beapplied. The wall thickness depends on the desired internal pressure andlies in the range of approximately 1 millimeter.

It is obvious that also rigid elements, for example, fastening devicesor hatches, can be integrated into the structure, provided that this isnot rendered impossible by a predetermined packaging volume.

Particularly, the foldable structures can also be used as carriers oftechnical and scientific sensors and devices, or as sail surfaces,whereby in such cases essentially two-dimensional arrangements areapplied.

The structure once inflated at the location of operation should remainfixed in its form and should not be folded anymore. Such a fixing ispreferably achieved in that the inner sides of the tubes are coated witha laminate 18 as indicated, for example, at one of the tubes 11 in FIG.1a and which laminate 18 only sets when in contact with a catalyzinggas. This gas can be added during inflation or after the structurehaving already assumed the final shape. There is thus no necessity ofmaintaining over a longer period the gas pressure within the tubes. Itis also possible to fix the structure subsequent to inflation, forinstance, by means of a setting filling material which is fed into thecavities of the tubes.

A further possibility of setting is that the membranes and/or the tubesundergo a chemical or physical curing by solar or thermal action or byadding a setting agent, such that the structure remains stable. Insofaras only the membranes are cured, the tubes have a supporting action onlyduring inflation and subsequently only serve to join the individualmembranes now rigidized to plates. A combination of fixing the tubes andcuring the membranes is also possible.

A spherical heat shield is illustrated in FIGS. 1a and 1b. A pluralityof ribs 11 project from a solid base ring 12 (FIG. 1a). All these ribs11 come together in a ring 13. The ring 13 as well as these ribs 11 arecomposed of flexible tubes and gas-tightly connected to each other,whereby the ribs 11 are directly adhesively bonded or welded with thering 13 at nodal points 16. The tubes 11 are fabricated such that theycomprise a curvature in the inflated condition and the skeleton thusassumes a spherical shape. The skeleton is inflated via a centralpressure source 17 as indicated in FIG. 1b of the drawings. At the ribs11 there is attached a plastic foil 14 which is stretched, afterinflation of the skeleton (FIG. 1b). This foil 14 comprises, forinstance, a reflecting coating and protects the pay load 15 against adetrimental heat radiation. A multi-layer or multi-phase flexible clothor foil (for example MLI) can be used as the foil 14.

The thermo-protective shield can be fastened by means of the solid basering 12 to a carrier element, a spaceship or even to the pay loaditself. The pressure source 17 and if need be the activating medium orfilling material for the fixation of the tubes are provided in the payload or the spacevehicle and connected via connecting lines with theskeleton (not shown in FIG. 1). In outer space the folded structure isunfolded according to the described method and fixed.

FIGS. 2a and 2b show a prismoidal foldable structure in the inflatedcondition. The base surface 21 is formed by tube struts 22 which formthe edges of a regular dodecagon (FIG. 2b) In radial direction there aremounted further struts 23 for reinforcing purposes. These struts 23converge in a fastening ring 24. The actual protective jacket 28 istentered by lengthwise struts 25, whereby such a strut 25 projects fromeach corner point of the base surface. The other ends of theselengthwise struts 25 are, in turn, coupled via struts 26, whereby thesestruts 26 lie in a plane inclined with respect to the lengthwise axis.All these struts 22, 23, 25 and 26 consist of flexible inflatable tubes.The protective jacket 28 can be made up of individual sections or, inthe case of smaller structures, can also be composed of one piece, whichare attached to the lengthwise struts 25 and, if necessary, to the ringstruts 22 and 23.

In order to be able to inflate the skeleton by means of one centralpressure source 17, the coupling elements 27 between the individualstruts are formed by tube connections. Such tube connections can alsoconsist of a flexible material, but can also be rigid in order todefine, for example, the angle between the lengthwise struts 25 and thebase surface 21. Therefore, in the illustrated protective shield,preference is given to rigid coupling elements 27, provided that noadditional struts or fixed elements are provided in order to achieve theright angle between the lengthwise struts 25 and the base surface 21.

FIGS. 3a and 3b show a shield very similar to the heat shield justdescribed above. However, in this shield the form of the base surface isobtained by two correspondingly structured membranes 30, at the outeredges of which there are attached struts 31 forming a closed ring. Thesetwo membranes 30 are stretched by inflation of the chamber between themembranes 30, thus also producing a twelve-angled base surface. In therecesses 32 of the membranes 30 there is provided a fastening ring 33.An additional stretching force can be achieved by inflation and fixingof the struts 31. Moreover, in order to raise the stability of the basesurface, the inner surfaces of the membranes can be coated, for example,with a curing laminate.

A further exemplary embodiment of the invention is illustrated in FIG.4. A shield in the form of an icosahedron encloses a chamber in whichdefined physical conditions can be maintained, since this chamber can beshielded from outer space. The inflated and fixed struts 41 firmly holdthe structure in this form without an overpressure having to prevailwithin this body. Triangular plastic membranes 42 are stretched betweenthe struts 41. Since the entire structure is stable independent of theinner pressure in the body, there is also the possibility of providinghatches which can be opened and closed for bringing, for example,experimental devices into the interior of the body. Five struts 41project from each corner point of the icosahedron and are joined to eachother by means of coupling elements 43 in order to render possible theinflation by means of a central pressure source. A fastening device 44in substitution of a plastic membrane can be provided at a side surfacein order to render possible the attachment to a spacecraft.

FIG. 5 shows a shading shield having a simple, essentiallytwo-dimensional structure. The shield possesses a circular form. Anannular tube 51 extends along the periphery of two membranes 52. It isobvious that only one individual membrane could be stretched out insteadof the two membranes 52. The shield is connected to the spacecraft via arigid arm 53 and protects the pay load 54 against solar radiation.

In FIG. 6 there is shown an exemplary embodiment of a coupling member60. In the illustrated example, three tube-shaped struts 61, 62 and 63,which are open at their ends, are joined to each other. These struts areadhesively bonded or welded at their open end faces 67 to the couplingmember 60. In order to raise the stability of these transfer locations,reinforcing rings or other reinforcing elements 65 can be arranged atthe outer side. In the event that, for example, the strut 61 is to beinflated only after the two other struts, then it is possible to providea diaphragm or a corresponding valve 66 in this strut or in the couplingmember 60. When gas from a pressure source is now infed via the strut62, this strut 62 and the strut 63 are first inflated. An inflation ofthe strut 61 also takes place but only after reaching a certain gaspressure definable by the diaphragm or the valve 66.

In the case of complex foldable structures, controlled valves can alsobe used to raise the reliability of a correct unfolding in outer space,such that the chronological sequence of the inflation of different partsof the foldable structure can be accurately determined.

FIG. 7 shows an example of a cut-away pattern for manufacturing atransfer piece or coupling member for joining four pipe struts. Sincethe nodal points between the tubes are subjected to a relatively largeload, high requirements are imposed upon their fabrication. Therefore,it has proven advantageous to provide as little as possible bonding orwelding locations at the nodal points. The manufacture of the transferpiece from one piece of flexible material, for example, fiber reinforcedcomposite material, is effected according to topological aspects in thatthe developed projection of the three-dimensional transfer piece isdefined. The respective corresponding straight edges (71, 72 and 73) ofthe illustrated cut-away pattern (70) are joined to each other, suchthat a three-dimensional transfer piece with four circular openingsresults, at which openings a tube each adjoins.

Furthermore, it is conceivable that the tubes as well as the transferpieces of the skeleton are fabricated from one piece in order to avoidunnecessary adhesive bonding or welding locations.

Although the invention has so far been described substantially inconjunction with protective devices, the foldable structure can be usedparticularly as a carrier of technical and scientific sensors anddevices or as a sail surface.

While there are shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto, but may be otherwise variously embodied and practicedwithin the scope of the following claims. ACCORDINGLY,

What we claim is:
 1. An inflatable foldable structure, comprising:aplurality of inflatable flexible tubes; a plurality of nodal pointsdefining gas-tight interconnections between predetermined ones of saidinflatable flexible tubes of said plurality of inflatable flexible tubesand permitting inflation of said plurality of inflatable flexible tubesand unfolding of the foldable structure to form a skeleton, saidplurality of inflatable flexible tubes forming, upon inflation andunfolding of the foldable structure, as said skeleton, a self-supportingstructural skeleton; a plurality of membranes affixed to respective onesof said plurality of inflatable tubes and extending between respectiveones of said plurality of inflatable flexible tubes; and a predeterminednumber of coupling members for providing interconnection between atleast some of said plurality of inflatable flexible tubes, saidpredeterminate number of coupling members permitting gas exchangebetween said at least some of said plurality of inflatable flexibletubes through said coupling members, wherein: each one of said couplingmembers is located at a respective one of said plurality of nodalpoints; each one of said coupling members constitutes athree-dimensional coupling member constituting a connecting member forproviding said interconnection between a predeterminate number of saidplurality of inflatable flexible tubes; and each one of said couplingmembers is formed in accordance with a predetermined topology of saidskeleton from a single coherent piece of flexible, gas-imperviousmaterial in the form of a cut-away pattern representing atwo-dimensional development of said three-dimensional coupling member.2. The inflatable foldable structure as defined in claim 1, furtherincluding:a plurality of valves; each one of said plurality of valvesbeing disposed in a respective one of said plurality of inflatableflexible tubes; each one of said plurality of inflatable flexible tubesdefining an interior space; the interior spaces of said plurality ofinflatable flexible tubes defining an interior of said skeleton uponinflation; and said plurality of valves serving to affect gas exchangewithin said interior of said skeleton upon inflation of the inflatableflexible tubes and unfolding of the foldable structure.
 3. Theinflatable foldable structure as defined in claim 1, further including:aplurality of thin diaphragms; each one of said plurality of thindiaphragms being disposed in a respective one of said plurality ofinflatable flexible tubes; each one of said plurality of inflatableflexible tubes defining an interior space; the interior spaces of saidplurality of inflatable flexible tubes defining an interior of saidskeleton; and said plurality of thin diaphragms serving to affect gasexchange within said interior of said skeleton upon inflation of saidplurality of inflatable flexible tubes and unfolding of the foldablestructure.
 4. The inflatable foldable structure as defined in claim 1,further including:a plurality of valves; each one of said plurality ofvalves being disposed in a respective one of said predeterminate numberof coupling members; each one of said plurality of inflatable flexibletubes defining an interior space; the interior spaces of said pluralityof inflatable flexible tubes defining an interior of said skeleton; andsaid plurality of valves serving to affect gas exchange within saidinterior of said skeleton upon inflation of said plurality of inflatableflexible tubes and unfolding of said foldable structure.
 5. Theinflatable foldable structure as defined in claim 1, further including:aplurality of thin diaphragms; each one of said plurality of thindiaphragms being disposed in a respective one of said predeterminatenumber of coupling members; each one of said plurality of inflatableflexible tubes defining an interior space; the interior spaces of saidplurality of inflatable flexible tubes defining an interior of saidskeleton; and said plurality of thin diaphragms serving to affect gasexchange within said interior of said skeleton upon inflation of saidplurality of inflatable flexible tubes and unfolding of said foldablestructure.
 6. The inflatable and foldable structure as defined in claim1, wherein:each one of said plurality of inflatable flexible tubes ismade of a fiber reinforced composite material.
 7. The inflatablefoldable structure as defined in claim 1, wherein:a predeterminatenumber of said plurality of inflatable flexible tubes assume a curvedshape upon inflation and unfolding of the foldable structure.
 8. Amethod of using an inflatable folded structure in conjunction withplacing a payload in outer space, said inflatable folded structurecontaining a plurality of inflatable flexible tubes, a plurality ofnodal points defining gas-tight interconnections between predeterminedones of said inflatable flexible tubes of said plurality of inflatableflexible tubes, and a plurality of membranes affixed to respective onesof said plurality of inflatable flexible tubes and extending betweensaid respective ones of said plurality of inflatable flexible tubes,comprising the step of:inflating said plurality of inflatable flexibletubes and thereby unfolding the inflatable folded structure to form aprotective element for the payload in outer space.
 9. The method asdefined in claim 8, wherein:said step of forming said protective elemententails forming a protective shield for said payload.
 10. The method asdefined in claim 8, wherein:said step of forming said protective elemententails forming a protective chamber for said payload.
 11. A method ofusing an inflatable folded structure in conjunction with placing apayload in outer space, said inflatable folded structure containing aplurality of inflatable flexible tubes, a plurality of nodal pointsdefining gas-tight, interconnections between predetermined ones of saidinflatable flexible tubes of said plurality of inflatable flexibletubes, and a plurality of membranes affixed to respective ones of saidplurality of inflatable flexible tubes and extending between saidrespective ones of said plurality of inflatable flexible tubes,comprising the step of:inflating said plurality of inflatable flexibletubes and thereby unfolding the inflatable folded structure to form acarrier for the payload in outer space.
 12. A method of using aninflatable folded structure in conjunction with placing a payload inouter space, said inflatable folded structure containing a plurality ofinflatable flexible tubes, a plurality of nodal points defininggas-tight interconnections between predetermined ones of said inflatableflexible tubes of said plurality of inflatable flexible tubes, and aplurality of membranes affixed to respective ones of said plurality ofinflatable flexible tubes and extending between said respective ones ofsaid plurality of inflatable flexible tubes, comprising the stepof:inflating said plurality of inflatable flexible tubes and therebyunfolding the inflatable folded structure to form a sail surface for thepayload in outer space.
 13. A method of producing a skeleton of apredetermined topology, comprising the steps of:prefabricating aninflatable folded structure containing a plurality of inflatableflexible tubes, a plurality of nodal points defining a plurality ofgas-tight interconnections between predetermined ones of said inflatableflexible tubes of said plurality of inflatable flexible tubes, and aplurality of membranes affixed to respective ones of said plurality ofinflatable flexible tubes and extending between said respective ones ofsaid plurality of inflatable flexible tubes; during said step ofprefabricating said inflatable folded structure, prefabricating, as saidinflatable folded structure, an inflatable folded structure which isstructured in correspondence with the predetermined topology of theskeleton; inflating said inflatable folded structure by using a pressuresource of gas and thereby unfolding said inflatable folded structure inorder to form said skeleton of said predetermined topology; said step ofinflating and unfolding said inflatable folded structure entailing thestep of inflating and unfolding said inflatable folded structure in asequence of inflating and unfolding steps; thereafter, stabilizing saidskeleton of said predetermined topology by said gas from said pressuresource of gas and thereby positionally fixing the inflated flexibletubes; and arranging pressure control means in said plurality ofinflatable flexible tubes for controlling said step of inflating andunfolding said inflatable folded structure in said sequence of inflatingand unfolding steps.
 14. The method as defined in claim 13, wherein:saidstep of arranging pressure control means in said plurality of inflatableflexible tubes entails arranging, as said pressure control means, aplurality of valves in said plurality of inflatable flexible tubes. 15.The method as defined in claim 13, wherein:said step of arrangingpressure control means in said plurality of inflatable flexible tubesentails arranging, as said pressure control means, a plurality of thindiaphragms in said plurality of inflatable flexible tubes.
 16. Themethod as defined in claim 13, wherein:said step of prefabricating saidinflatable folded structure entails prefabricating an inflatable foldedstructure further containing a predeterminate number of coupling membersinterconnecting at least some of said plurality of inflatable flexibletubes; and arranging pressure control means in each one of saidpredeterminate number of coupling members for controlling said step ofinflating and unfolding said inflatable folded structure in saidsequence of inflating and unfolding steps.
 17. The method as defined inclaim 16, wherein:said step of arranging pressure control means in saidpredetermined number of coupling members entails arranging, as saidpressure control means, a predeterminate number of valves in saidpredeterminate number of coupling members.
 18. The method as defined inclaim 16, wherein:said step of arranging pressure control means in saidpredeterminate number of coupling members entails arranging, as saidpressure control means, a predeterminate number of thin diaphragms insaid predeterminate number of coupling members.
 19. The method asdefined in claim 13, wherein:said step of prefabricating said inflatablefolded structure entails affixing said plurality of membranes topredetermined mounting locations at said plurality of inflatableflexible tubes; and said step of inflating and unfolding said inflatablefolded structure in order to form said skeleton of said predeterminedtopology entailing the step of aligning said plurality of inflatableflexible tubes and said plurality of membranes along said predeterminedmounting locations.
 20. The method as defined in claim 19, wherein:saidstep of aligning said plurality of inflatable flexible tubes and saidplurality of membranes along said mounting locations entails bendingsaid plurality of inflatable flexible tubes along said predeterminedmounting locations.
 21. A method of producing a skeleton of apredetermined topology, comprising the steps of:prefabricating aninflatable folded structure containing a plurality of curable inflatableflexible tubes, a plurality of nodal points defining a plurality ofgas-tight interconnections between predetermined ones of said curableinflatable flexible tubes of said plurality of curable inflatableflexible tubes, and a plurality of membranes affixed to respective onesof said plurality of curable inflatable flexible tubes and extendingbetween said respective ones of said plurality of curable inflatableflexible tubes; during said step of prefabricating said inflatablefolded structure, prefabricating, as said inflatable folded structure,an inflatable folded structure which is structured in correspondencewith the predetermined topology of the skeleton; inflating saidinflatable folded structure by using a pressure source of gas andthereby unfolding said inflatable folded structure in order to form saidskeleton of said predetermined topology; said step of inflating andunfolding said inflatable folded structure entailing the step ofinflating and unfolding said inflatable folded structure in a sequenceof inflating and unfolding steps; thereafter, stabilizing said skeletonof said predetermined topology by curing and thereby positionally fixingthe curable inflated flexible tubes; and arranging pressure controlmeans in said plurality of curable inflatable flexible tubes forcontrolling said step of inflating and unfolding said inflatable foldedstructure in said sequence of inflating and unfolding steps.
 22. Themethod as defined in claim 21, wherein:said step of arranging pressurecontrol means in said plurality of curable inflatable flexible tubesentails arranging, as said pressure control means, a plurality of valvesin said plurality of curable inflatable flexible tubes entailsarranging, as said pressure control means, a plurality of valves in saidplurality of curable inflatable flexible tubes.
 23. The method asdefined in claim 21, wherein:said step of arranging pressure controlmeans in said plurality of curable inflatable flexible tubes entailsarranging, as said pressure control means, a plurality of thindiaphragms in said plurality of curable inflatable flexible tubes. 24.The method as defined in claim 21, wherein:said step of prefabricatingsaid inflatable folded structure entails prefabricating an inflatablefolded structure further containing a predeterminate number of couplingmembers interconnecting at least some of said plurality of curableinflatable flexible tubes; and arranging pressure control means in eachone of said predeterminate number of coupling members for controllingsaid step of inflating and unfolding said inflatable folded structure insaid sequence of inflating and unfolding steps.
 25. The method asdefined in claim 24, wherein:said step of arranging pressure controlmeans in said predetermined number of coupling members entailsarranging, as said pressure control means, a predeterminate number ofvalves in said predeterminate number of coupling members.
 26. The methodas defined in claim 24, wherein:said step of arranging pressure controlmeans in said predetermine number of coupling members entails arranging,as said pressure control means, a predeterminate number of thindiaphragms in said predeterminate number of coupling members.
 27. Themethod as defined in claim 21, further including the steps of:coating aninterior surface of said inflatable flexible tubes with a curablelaminate; adding a chemical curing agent to said gas of said pressuresource; and said step of stabilizing said skeleton of aid predeterminedtopology by curing and thereby positionally fixing said inflatedflexible tubes entailing the step of chemically curing said laminatecoating said interior surface of said inflatable flexible tubes underthe action of said chemical curing agent added to said gas and therebyrigidifying said skeleton of said predetermined topology.
 28. The methodas defined in claim 21, further including the steps of:coating aninterior surface of said inflatable flexible tubes with a curablelaminate; using, as said gas of said pressure source, a gas constitutinga catalyst for curing said curable laminate; and said step ofstabilizing said skeleton of said predetermined topology by curing andthereby positionally fixing said inflated flexible tubes entailing thesteps of catalytically curing said laminate coating said interiorsurface of said inflatable flexible tubes under the action of said gasconstituting said curing catalyst and thereby rigidifying said skeletonhaving said predetermined topology.
 29. The method as defined in claim21, further including the steps of:coating an interior surface of saidinflatable flexible tubes with a thermally curable laminate; and saidstep of stabilizing said skeleton of said predetermined topology bycuring and thereby positionally fixing said inflated flexible tubesentailing the steps of thermally curing said laminate coating saidinterior surface of said inflatable flexible tubes by exposing saidinflatable flexible tubes and said laminate to thermal radiation. 30.The method as defined in claim 21, wherein:said step of prefabricatingsaid inflatable folded structure entails affixing said plurality ofmembranes to predetermined mounting locations at said plurality ofinflatable flexible tubes; and said step of inflating and unfolding saidinflatable folded structure in order to form said skeleton of saidpredetermined topology entailing the step of aligning said plurality ofinflatable flexible tubes and said plurality of membranes along saidpredetermined mounting locations.
 31. The method as defined in claim 30,wherein:said step of aligning said plurality of inflatable flexibletubes and said plurality of membranes along said mounting locationsentails bending said plurality of curable inflatable flexible tubesalong said predetermined mounting locations.
 32. The method as definedin claim 21, wherein:said step of prefabricating said inflatable foldedstructure entails prefabricating an inflatable folded structure furthercontaining, as said membranes, curable membranes; and said step ofstabilizing said skeleton of said predetermined topology by curingentails the further step of curing and thereby positionally fixing thecurable membranes.